( Reaffirmed 2005 ) IS : 10334- 1982 Indiah Standard CODE OF PRACTICE FOR SELECTION, SPLICING, INSTALLATION AND PROVIDING PROTECTION TO THE OPEN ENDS OF CABLES USED FOR CONNECTING RESISTANCE TYPE MEASURING DEVICES IN CONCRETE AND MASONRY DAMS Hydraulic Structures Jnstrumentation In Sectional Committee, BDC 60 Chairman SIlR1 H. c. VERlCIA Repesenting personal capacity [ Associated Instrument Manu,fncturers ( India ) Privak? Ltd, 2G-?7 Asaf Ali Road, New Delhi ] Members Central Scientific Instruments Organization ( CSIR ), Chandigarh National Physical Laboratory, New Delhi DR B. K. AG~XXVAL~~ SHltl N. BIiooTIIA1;TNo.&nT Kerala State Electricity Board, Trivandrum CHIEF ENGINEER ( CIvrL ) Damodar Valley Ccrporation, P. 0. Maithon Dam CHIEF ENOINRER ( DESIGN 6L Irrigation Department, Government of Punjab, Chandigarh RESEARCH ) SHRI PREBLAD SINGH ( Alternate ) CHIEF ENGINEER ( IRRIGATION ) Irrigation Department, Government of Tamil Nadu, Madras INSTITUTE OF DIRECTOR, HYDRAULICS & HYDROLOGY ( Alternate ) CH;;~~NGINRRR & DIRECTOR, Irrigation Department, Government of Maharastra, Bombay SHRI 0. P. DATT.~ Beas Designs Organization, Nangal Township S HIXI0. R. M~rl~a ( Alternate ) SHJEI R. N. AGGARWAL ( Alternate ) Central Water & Power Research Station, Pune ~~IItECTOI~ SHRI S. L. MOKHASHI ( Alternate) EXECUTIVE ENGINEER, TESTTNG Ram Ganga Project, Kalagarh Sr QUAI,ITY CONTROL Phillips India Ltd, Bombay SHRI P. GO~WAMI SHI~I K. BASU ( Alternate ) SHRI S. S. A~ARW.U, ( Continued on page 2 ) @ Copyright 1983 INDIAN STANDARDS INSTITUTION `l`hls publication is protected under rhe Indian Copyright Acf ( XIV of 1957 ) and reproduction in whole or in part by any means except with written permission of the publisher shall be deemed to be an infringement of copyright under the said Act. IS:10334 -1982 ( Continued from page 1 ) Members Representing Ckntral Water Commission, New Delhi SHRI S. N. GURU Rnu SHRI G. S. NAR~YA~A ( Alternate ) Vasi Shums & Co Private Ltd, Bombay SHRI 2. M. KARACHIWAL.~ Irrigation Deprartment, Government of Gujarat, SHRI R. G. PATEL Gandhinagar Irrigation Department, Government of Andhra DR J. PU~USHOTTAM Pradesh, Hyderabad CHIBF ENGINEER, SRISAILAM PROJECT ( Alternate ) Central Board of Irrigation & Power, New Delhi SECRETARY DEPUTY SECRETARY ( Alternate ) Instrument Manufacturers ( India ) Associated SRRI SUBHASH SRARMA Private Ltd, New Delhi Director General, IS1 ( Ex-O&O Member ) SHRI G. RAMAN, Director ( Civ Engg ) Secretary SHRI K. K. SEARMA Deputy Director ( Civ Engg ), IS1 IS :10334-1982 Indian Standard CODE OF PRACTICE FOR SELECTION, SPLICING, II'WTALLATION AND PROVIDING PROTECTION TO IHE OPEN END-SOF CABLES USED FOR CONNECTING RESISTANCE TYPE MEASURING DEVICES IN CONCRETE AND MASONRY DAMS ~ 0. FOREWORD 0.1 This Indian Standard was adopted by the Indian Standards Institution on 29 October 1982, after the draft finalized by the Hydraulic Structures Instrumentation Sectional Committee had been approved by the Civil Engineering Division Council. 0.2 Rubber insulated and rubber sheathed 3-conductor and 4-conductor stranded flexible cords are used for connecting highly accurate measuring instruments embedded in concrete and masonry dams to suitable terminal boards located in the galleries of the dam. 0.3 A large portion of the cord is embedded. in the concrete or ,mortar in the dam and hence rugged construction, positive imperviousness to moisture at higher pressure, uniform conductor resistance and long life . are of paramount importance. The usually severe conditions to which this cord is subjected include ambient air and ccmcrete temperatures of 50"C or so, excessively damp locations, alkaIine reaction of concrete and rough treatment during installation. 0.4 In the field, in order to add additional length of cable already attached to the instrument for joining it to the terminal locatecl in the gallery, it is necessary to splice. the cable ends field laboratory prior to the embedment of the instruments structure. to that boards in the in the 0.5 Where the ends of cables attached to the instrument are left loose or uncovered for a while until these are properly terminated, a good care for, prevention of moisture or water from entering the instrument through the cable ends, is considered necessary. 3 IS:10334- 1982 0.6 It is not practical to vulcanize natural rubber with synthetic rubber. It is, therefore, necessary that the cable to be used should be of the same specification as that attached to the instrument. necessary 0.7 In the case of masonry dams, it is considered horizontal and vertical runs of cable through conduits. to take 1. SCOPE 1.1 This standard covers the details of specifications of cables, method of splicing and installation of cables, mode of delivery, inspection and test to be carried out on the material used in the manufacture of cables as also on finished cable, pre-embedment tests, cable end protection and fixing the size of conduits. 2. CABLE SPECIFICATIONS 2.1 Type, Size and Ratings - The cord sha!l consist of three or four cores of tinned annealed high conductivity copper wire with a nominal area of each conductor of 1'5 sq mm insulated with moisture and heat resisting elastomer or PVC insulation and jacketed with elastomer or Elastomer insulated cord shall comply with PVC sheathing. and PVC insulated cord shall comply with IS : 9968 ( Part I )-1981" IS : 694-19777. 2.2 Method of Delivery - The cord shall be in lengths 1 000 m with inner and outer ends of each length extending metre outside the reel to facilitate sampling for test purposes. of 300 to at least one 2.3 Inspection and Tests - Proper inspection and testing shall be carried out with a view to examining the cables in accordance with the or IS : 694-1977t, provisions contained in IS : 9968 ( Part I j-1981* whichever is applicable. 3. CABLE SPLICING PROCEDURE instruments for often supplied with one that the work of cable required. Faulty splices 3.1 The embedment in concrete or masonry dams are metre of multi-core cable attached initially, SO splicing shall be done where cable extension is are generally a potential source of trouble. *Specification for elastomer-insulated cables : Part I For working voltages up to and including 1 100 volts. tspecification for PVC insulated cables for working voltages up to and including 1 100 volts ( second revision ). 4 IS:103343.2 There are three methods terminal boxes, namely: a) Vulcanized b) Rubber c) Self-bonding rubber tape. steps shall for cable splicing for cable extension 1982 to the splice, and sleeve covering, 3.2.1 Vulcanized Rubber Splice - The following in the procedure -for vulcanizing cable splices: be followed a) The cable sheath for 80 mm from the cable end shall be removed and joint made ,of the individual pair of conductors staggered by 25 mm lengths ( Fig. 1A ) so that the finished splices do not lap; b) `Ten millimetres of rubber insulations from each conductor be cut, while taking care not to damage the conductor; c) The individual conductors same, colours put into ( Fig. IB and 1.C ); shall shall be twisted and conductors of the a copper sleeve and then soldered be wiped by repair tape d) The surface of copper sleeve and insulation shall using benzene absorbed clean cloth and unvulcanized wound on it ( Fig. 1D ); e) On completion of conductor splicing, the ends of insulations are marked on the cable and unvulcanized tape tightly wound along the whole jointing portion. In this case, in order to obtain a strong adhesion, the surface of sheath, on which un,vulcanized tough rubber tape is to be wound shall be roughened for length of about 40 mm by use of file or knife, and polychloroprene rubber paste shall be applied ( Fig. 1E ); the splice shall be wrapped with unvulcanized f) After drying, tough rubber tape, carrying the tape up onto the sheath, at least two layers half-lapped ( see Fig. 1F ); g) Wrapping on the splice shall be completed with vulcanizing tough rubber tape, and all projections shall be cut off with a knife just before completion of the final layer; 11) Continue until the vulcanizer; the splice is built up to the size of the mould of j) Silicone oil or soapwater shall be applied on the inside surface of metal mould of the vulcanizer. The vulcanizer shall be connected and energized according 5 to the manufacturers' instructions; IS:l0334- 1982 k) After the indication of the vulcanizer has, reached 100°C ( preheating point ), vulcanizer shall be opened and the splice put in the metal mould; mould shall be gradually and tightened until it While energizing, the m> is uniformly fastened; 4 The temperature shall be raised to 140-160% and kept at that level for about 30 min. Then energizing shall be stopped and after the temperature comes down to about 12O"C, the metal mould shall be opened and the splice shall be taken out and excess rubber trimmed off. The following steps shall be followed: 3.2.2 Rubber Sleeve Covering - 4 Cable shall be removed and cable ends shall be joined in accordance with the procedure indicated. in 3.2.1(a), through 3.2.1(c). copper sleeves Insulating sleeves shall be provided over ( Fig. 2A and 2B ); jointed conductors shall be enclosed in a rubber sleeve or plastic pipe having open gap, by passing the conductors through the open gap. The rubber sleeve shall be wound on two grooves fixed one on each side of the splice ( Fig. 2C ). Voids between the rubber sleeve and jointed conductors shall be filled with cable compound; b) The Finally, the splicing portion shall be wound with adhesive vinylchloride tape ( Fig. 2D). 3.2.3 Self-Bonding Tape - The self-bonding tape is made from synthetic resin and rubber, which is a good electric insulator and is particularly durable against watering and aging. The following steps shall be followed: a) Sheath of the cable attached to the instrument shall be removed and conductors spliced in accordance with the procedure given in 3.2.1(a); and After jointing the conductors b) Cover with self-bonding tape. each of the conductors shall be wrapped with the tape extending it 30 to 40 mm on each side of the splice of individual conIn order to obtain a strong adhesion, the surface of ductors. the sheath on which self-bonding tape is to be wound shall be roughened for a length of about 30 mm by the use of pumice, file or knife. The conductors shall then be assembled in a bench and wrapped with the tape extending to make a smooth rounded cross-section. 6 IS:10334 - 1982 TWIST IN THIS MANNER7 1 +-20-l L COPPER SLEEVE 18 COPPER SLEEVE r WRAPPEO UNVULCANISEO REPAIR 10 PENCILLEO ROUGHENED UNVULCANISEO TOUGH RUBBER SHEATH 1F All dimensions in millimetres. FIG. 1 VULCANIZED RUBBER SPLICE 7 IS : 10334 - 1982 INSULATING 2A t-2oi I f 1 28 t NOTE compound Ends of rubber sleeve through each gap. /--ADHESI'VE &all be tied with wire TAPE before pouring cable VINYLCHLORIDE All dimensions FIG. in millimetres. SLEEVE 8 COVERING 2 RUBBER IS: 10334 - 1982 4. CABLES AND CONDUITS 4.1 In estimating the length of the cable to be added, a suitable route between the point of embedment of the instrument and the terminal station in the gallery shall be selected by a study of the drawing. In selecting the route, due consideration shall be given to the construction procedures involved in placing the concrete where the instrument is to be embedded and to possible obstructions along the chosen route. After the selected route has been verified, the length of cable required shall be estimated, and a small amount, usually 10% or 1'5 m, whichever is larger, shall be added to allow for extra length required due to normal variation from the selected route. Length of cable should be limited to 75 m as far as possible. cables run within conduits in masonry and concrete, 4.2 In genera!, both in horizontal and vertical directions. Separate conduit should be used for each individual lift. The conduit may be of any material which will not collapse i,n fresh concrete, such as galvanized iron, or rigid PVC. The size of the conduit may be chosen by drawing circles to represent the diameter of the cables. In order to allow for pulling friction, provide for one and a half times the number of cables where the conduit is of short length and up to twice the number of circles, as there are cables where the runs are long or Circumscribe these circles with a larger one there are many bends. to find the inside diameter of the conduit. 4.2.1 The size of the conduits TABLE No. OF CABLES TO BE DRAWN (1) 1 may also be chosen according CAPACITIES to Table 1. -~ CONDUIT MINIMUM INTERNALDIA OFTHE CONDUIT REQUIRED INTERNAL MAXIMUM CROW-SECTIONAL AREA OFCONDUITTHAT MAY BE OCCUPIED BY CABLES (3) 45% 30% 40% 38% For 5 or more cables 35% runs of length not exceeding (2) 1'49 d ( see Fig. 3 A ) 2'58 d ( seeFig. 3 B ) 2.74 d ( see Fig. 3 C ) 3.24 d ( see Pig. 3 D ) 3.78 d ( see Fig. 3 E ) 1 2 3 4 5 NOTE - These capacities are valid only for conduit 40 metres. 9 IS : 19334- 1982 d 3.A 3E 3c diameter of indicate group in terms of cable diameter d. FIG. 3 cables and minimum internal NOTE - lliagrams diameter of conduit COMXJITCAPACITIES 10 IS :10334-1982 4.2.2 When all cables are not of the same size, the conduit shall be worked out on percentage basis. 4.2.3 For diameters diameter and thicknesses of conduits see IS : 1653-1972*. 4.3 Where a group of cables is to be run horizontally in a lift, they may be taped together at intervals and laid on the top of the next to last layer of concrete in the lift, covered with pads of fresh concrete throughout their length, and placement of the final concrete lift layer allowed bto proceed in the normal manner. Leads of single or pairs of cables may be `walked into' the concrete. 4.4 Cables of instruments located above terminal reading station are run in downward conduit from lift containing instrument with separate conduits serving each individual lift. Each cable shall be threaded individually into the conduit, SO that each cable will be required to At the entrance of the cables into the support only its own weight. conduit, suitable protection, such as padding with burlap, should be provided around each cable and in the interstices between the cables to prevent sharp bends and to prevent the entrance of concrete and grout into the conduit. 4.5 Cable leads shall be run upward when the instruments are located below terminal reading station, without conduit from the lift in the case of concrete dam and within conduits in the case of masonry dam, Reinforcing bar shall be embedded in the concrete of successive lift for The cables shall be tied to the reinforcing providing support for cables. bars, at short intervals before placing each lift and the remainder of the cable coiled and hung clear of the fresh concrete. 4.6 In the general case where a number of cables from widely separated points are collected at one central point and run downward in may be run in two steps. A collecting box or conduit, the cable concrete form is erected around the grouped conduits, so that the lift is left about 450 mm below the conduits. During the placement of the concrete in which the meters are embedded, the cables should be brought horizontally to the collection point and then coiled and hung out of the fresh concrete. As soon as the concrete has set sufficiently to bear traffic, the cable coils shall be taken down the conduit to the terminal boards. The advantage is that it is much easier to sort and run cables when they are not muddled with fresh concrete. 4.7 If the cable leads are to cross contraction joints in the structure, a slack cable recess should be provided at the crossing point. This may consist of a wooden box block out, forming a recess into which the cable *Specification for rigid steel conduits for electrical wiring ( second revision ). 11 IS :10334- 1982 will run. During placement of concrete in the adjacent block, a 300 mm loop of slack cable should be left in the unfilled block out and the remaining length of cable laid in the usual manner. 5. CABLE END PROTECTION water from sealed. entering the instru- 5.1 In order to prevent moisture and ments, the cable ends should be suitably 6. PRE-EMBEDMENT RESISTANCE MEASUREMENTS 6.1 Prior to embedment of instruments in the newly placed concrete, each instrument shall be thoroughly checked for meter resistance as also for lead resistance and these shall be entered in the pro forma given in Appendix A. The resistance ratios before splicing and after splicing shall also be recorded in the pro forma meant for recording pre-embedThe pre-embedment tests quite often prove valuable during ment tests. the analysis of data. APPENDIX ( Clause 6.1 ) PRO FORMA FOR ~&stance Project Air temperature Wet Bulb Temperature I. RESISTANCE i) Red-black iii) Green-black II. RATIO i) Direct ii) Reverse INSTRUMENT BEFORE .I RECORD OF A PRE-EMBEDMENT RESISTANCE MEASUREMENT Type Pore Pressure Meters Instrument Manufacturer's Project No. Location CABLE SPLICING of one pair No. ii) Red-green iv) Resistance ONLY ratio ( white-green-black) ratio ( black-green-white) 12 IS : lo334 - 1982 III. INDIVIDUAL i) Length iii) Green-black IV. RATIO INSTRUMENT CONDUCTOR RESISTANCE ii) Black iv) Resistance WITH ) ) CABLE one pair i) Direct ratio ( red-black-green ii) Reverse ratio ( green-black-red Date of Test: Date of Embedment: Name and Signature OBSERVER Notes: of INTERNATIONAL Base Unit@ QUANTITY SYSTEM OF UNITS ( SI UNITS) UNIT SYMBOL Length Mass Time Electric current Thermodynamic temperature Luminous intensity Amount of substance Supplementary QUANTITY metre kilogram second ampere kelvin candela mole m kg s A K cd mol Units UNIT radian steradian SYMBOL rad sr Plane angle Solid angle Derived Units QUANTITY UNIT newton joule watt weber tesla hertz siemens volt Pascal force SYPBOL N J W Wb T Hz S V Pa 1 1 DEFINITION N = 1 kg.m/s* J = 1 N.m 1 V.s Force Energy Power FlUX 1 W=lJ/s lWb= 1 1 1 T = 1 Wb/m S 0 1 A/V V = 1 W/A Flux density Frequency Electric conductance Electromotive Pressure, stress 1 Hz = 1 c/s (s-1) 1 Pa = 1 N/m'